Synchronizing system



UCt. 16, 1934. c F. JENKINS 1,976,784-

SYNCHRONI Z ING SYSTEM Original Filed 1,21, 1927- s SheetsSheet 1 I L P M Y I @5 16% Gbtowmf Oct. 16, 1934.

C. F. JENKINS SYNCHRONI Z ING SYSTEM 0riginal Filed July 21, 1927 3 Sheets-Sheet 2 avwamtoz Oct. 16, 1934-. C JENKINS 1,976,784

SYNCHRONIZING SYSTEM Original Filed July 21, 1927 5 Sheets-Sheet 3 Patented-0d. 16, 1934 I i k will g simcnnomzmo srs'rm vcinem- Francis 1am, ashington, D. c., aa-' linenbymcaneaaai'gnmentatonadiocorporation-of America, a corporation of Delaware application-July 21,1921, Serial No."

will

807,515, Patent No. 1,7,645111110'24,

Divided and this llipllcatiolr'May 22, 193.,

No. 4545s:

1? reiationshipbetween the transmitting and receiving apparatus.

. object of my invention is to devise novel relarpppantm t mb d! p nding to currentvariations of relatively high fre- .wlnvc nticnisillustratedlntheaccompany ing drawings in which like reference characters Figured a diagrammatic showing of. one

, form'ot employed at the receiving Pigslisadiagrammatic repraenta'tionof a form of, pparatus employed at the receiving station; and

- Fig; 3 is athird modificationiof the. invention.

. InI igureLamotorMisarrangedto drivea cylindrical drum C upon which is mounted the surface -or,;film which is to, receive the picture being transmitted. 'lhe'motor If comprises an armatureAandafieidwindingF,eachof which is supplied with current from the battery B. The armature circuit of the motor is. completed from battery-B through the output circuit of amplifier A8, armature A, and back to battery 13. The armature also has ashunt circuit 1mm battery B through resistance R1. The receiving'station is provided'with a radio receivingset comprising'a detector D1 and an amplifier A1. Connected to the. output circuit of amplifier A1 is a second amplifier A2, the out put circuit of which contains an incandescent lamp L. The picture recording apparatus is also connected to the output circuit of amplifier A1 and comprises. for example, a solenoid 5 arranged tooperate aninking pen P. A lens L1 is arranged to gather the divergent rays proceeding from lamp L and focus them .upon a lightsensitive cell LS connected in the input circuit of amplifier A3. A disc D, provided with a series of holes arranged around its periphery, is mounted .upon the shaft of motor A and is arranged to rotate in the path of the rays of light projected upon light-sensitive cell 8 by the lens L1. The

width of the openings in disc D is preferably equal to half the distance between the openings, al-

causes the'pen P to record uponthe picture reing interruptions or variations. A portion of the though this ratio may be varied considerably if The operation of Figure 1 is as follows: Itistobeunderstoodthat aradiowaveisbeing transmitted from the transmitting station and that the wave ismodulated in accordance with the 118111: variations of successive elementary areas of Picture being transmitted and also in accordance with the speed of rotation of the transmitting apparatus. The synchronising modulations bear a definiterelation to the speed of the. transmitting apparatus and may be produced-in any desired manner, but I prefer to employ as light chopper for. this purpose, as discloud in my Patent No. 1,694,065granted1Deember 4, 1929. line modulated wavelis'mceived at the receiving station and detected by detector D1 to derive therefrom. low frequency currents which represent bothj the picture lightyariations and the synchronizing meomposite current is supplied to' amplifier A1 where it is amplified and supplied to the output circuit. The 'ampli- 'fied current is supplied to the recording apparatus which responds to the picturetvariations and ceiving surface, mounted upon drum (Link marks 1 corresponding to the dark portions of the picture being transmitted.- The recording apparatus, need not necessarily respond to the synchronizcuritnt in the output circuit of amplifier A1 is 3 supplied to the input circuit of amplifier A2, and

Iisalso subject to'controlby disc D in the follow-'- ing manner: In case the motor M-is rotating at such speed that the holes in disc-D rotate past the beam at a frequency equal to the frequency of the synchronizing variations, andthe phase relation of the disc with respect to the synchronizing impulses is such that each pulse reaches a maximum as a hole in discD is centered with respect no to the beam oflight, the effect of the'beam of solid portion of disc D is passing in front of the light ray the effect of the ray upon light-sensitive cell LS will be a minimum, and the current variations produced in the armature circuit of motor M will be very small. For intermediate phase relations of the holes in disc D with respect to the synchronizing pulses, the efiect of the light rays upon the light-sensitive cell will be to produce intermediate values of current variation in the armature circuit. The speed of motor M is adjusted by resistance R1 to such value that it is slightly below the desired synchronous speed. The effect of the current pulses produced by the light-sensitive cell LS in the armature circuit is to increase the motor speed. Accordingly, disc D will assume such phase relation with respect to the synchronizing pulses or variations of lamp L that the amplitude of the current pulses produced by LS is just suiiicient to. maintain the motor in synchronous operation with the incoming synchronizing pulses. In case the load upon the motor is increased for any reason, disc D will lag behind the synchronizing pulses by an amount suflicient to increase the amplitude of the current pulses produced by light-sensitive cell LS and to thereby supply to the armature A, increased current suflicient to accommodate the increased load. Conversely, if the load is decreased from its normal value, the motor will momentarily speed up and cause disc D to advance in phase relation with respect to the synchronizing variations, and the resulting current pulses produced by light-sensitive cell LS will be correspondingly reduced, and the motor will be prevented from getting out of synchronism.

The arrangement shown in Fig. 2 is the same as that shown in Figure 1, except for the details of the motor control arrangement. In this figure, as in Figure 1, both the armature and the field of the motor are supplied with current from battery B. The armature circuit of the motor also includes an adjustable resistance Rl. In a shunt path around resistance R1, a rotating commutator CM mounted upon the shaft of the motor is connected in series with contacts GT-Cl? of a special electric relay; The relay comprises a glass tube MF provided with an electrode E mounted in each end thereof. The tube is filled with an acidulated solution and also contains a globule of mercury GM immersed within the solution. The insulated contacts GTCP are mounted upon the tube and extend into the solution and normally contact with the globule of mercury as shown in the figure. Electrodes E-E are connected to the output circuit of amplifier A1, and contact points GT-CP are connected in series with commutator CM in a shunt circuit around resistance R1 in the armature circuit.

The operation of Figure 2 is as follows:

The speed of motor M is adjusted by resistance R1 until it is slightly lower than the desired synchronous speed. With contacts GT-CP bridged by mercury GM, resistance R1 will be periodically short-circuited by commutator CM, twice for each revolution, and the time of short-circuit will de-- pend upon the extent of the contact surface of the commutator and upon the speed of the motor.

When amplified low frequency current from amplifier A1 flows through the relay between electrodes E-E, the globule of mercury elongates and breaks the connection between contact points GT-CP. The connection between contacts GT-CP will, therefore, be broken synchronously with the synchronizing impulses.

It will thus be seen that the effectiveness of resistance R1 in the armature circuit is dependent upon the conjoint action of the commutator CM and the relay, and the time of short-circuit of resistance R1 is dependent upon the phase relationship existing between the commutator and the relay. If the commutator and the relay operate simultaneously to close their respective contacts, resistance R1 will be effectively cut out of the armature circuit for a maximum period. If the commutator and relay become displaced in phase in their operation the period of shortcircuit will be reduced and resistance R1 will have greater effect in limiting the speed of motor M. Accwdingly, with a given load upon the motor and with a given adjustment of the circuits, the motor M will automatically adjust commutator CM to such phase relation with respect to the relay operation that the effectiveness of resistance R1 in the armature circuit is just sufiicient to maintain the motor at synchronous speed. If the load upon the motor is increased for any reason, the commutator CM tends to lag behind the operation of the relay and thereby increases the period of short-circuit of resistance R1, which will tend to increase the speed of the motor. Commutator CM will automatically assume such position that resistance R1 is effectively short-circuited for a period of time sufiicient to increase the armature current by an amount necessary to compensate for the increased load. Conversely, if the load upon the motor is decreased, the commutator CM tends to advance in phase relation with respect to the operation of the relay and thereby decrease the period of short-circuit of resistance R1 which will offset the tendency of the motor to increase in speed above synchronous speed.

The arrangement shown in Fig. 3 is the same as that shown in Fig.. 2, except for the details of the relay. The relay shown in Fig. 3 comprises a contact arm CA pivoted at a point (a). C0- operating with the contact arm is a stationary contact plate CP. The arm CA is normally held out of contact with plate CP by means of a wire W, one end of which is attached to the arm and the other end is anchored to a fixed terminal. A spring S1 is attached to the arm CA and tends to cause the arm to contact with plate CP. Wire W is connected to the output circuit of amplifier A1, and contact arm CA and plate CP are connected in series with commutator CM in a shunt path around resistance R1. Wire W is made of such material and such diameter that it is readily heated by current supplied from amplifier A1. The effect of the pulsating current flowing in wire W is to cause the wire to become elongated periodically and in synchronism with the synchronizing impulses. Spring S1 causes the arm CA to contact with plate CP each time wire W is elongated by the amplified current. Thus, the relay contacts will be closed periodically and in synchronism with the synchronizing signals. The action of the arrangement shown in Fig. 3 will be readily understood from the foregoing explanation of the operation of Fig. 2.

It is apparent that the arrangements shown in Figs. 2 and 3 will also operate with only the relay connected in the shunt path around resistance R1, and the commutator CM connected in the armature circuit so as to periodically interrupt the total armature current.

While I have shown symbolically, and for the purpose of illustration only, a recording apparatus comprising an inking pen P operated by a magnet S, it will readily be understood that any 1,976,784 other well known type or recording WWW may be employed, such Iorexample, as well known photographic recording apparatus.

TheJclrcuits o! the relays have very little inductance and otter smallimpedance tohighirequency currents. i i

It is to be noted that in Fig. 1, I employ a form 01 electric relay having no moving mechan ical parts, and the motor control system does not employ vibrating or sliding electric contact devices.

What is claimed is:

i. In a synchronizing system the combination or means tor producing synchronizing current variations, a motor to be synchronized, a source o1 means for producing synchronizing current variations a motor to be synchronized, a so'urce or current for operating said motor, means com- 1 prising an expansible member for translating said a current into corresponding mechanical vibrations. means" to translate said vibrations into current variations in the motor circuit, means controlled in accordance with the speed of the motor for varying the eiIect or said vibrations upon the current in the motor circuit.

3'. In a synchronizing system the combination or means for producing synchronizing current variations, a. motor to be synchronized, a source oi current tor operating said motor, means comprising an expansible member for translating said current into corresponding mechanical vibrations, means fortranslate said vibrations into current variations in the motorcircuit, means for controllingthe eflect of said vibrations in accordance with the relative phase displacements between the angular rotation of the motor and the synchronizing variations.

4. The method of synchronizing the operation of a motor with synchronizing signals, which consistsin-translating the signals into corresupplied to the motor inaccordance with said variations and varying the effect of said variations in accordance with the relative phase displacements between the angular rotation 01 the motor and the synchronizing impulses.

, 6.1:: a synchronizing system the combination of means for producing synchronizing current variations, a motor to be, synchronized, a source or current for operating said motor, an expansible member controlled by the synchronizing current, a circuit controlled by said expansible member and adapted to supply current variations to said motor circuit and an interrupter member driven by the motor to conjointly control the impulses delivered to the motor circuit.

n In a system the combination. o! means for producing synchronizing current variations, a motor to be synchronized, a resistance in the motor circuit, a periodic circuit in-.

terrupter operated by the motor, and connected in a path in shunt to said resistance, a'second interrupter inserted in said shunt path comprising a' pair of spaced contacts normally held apart by heat responsive means, said means being controlled by said synchronizing current to cause said contacts to close periodically said shunt path.

. 8. In a synchronizing system the combination of means for producing synchronizing current variations, a motor to be synchronized, a resistance in the motor circuit, a periodic circuit interrupter operated by the motor and connected in a path in shunt to said resistance, a stationary contact member normally held out of engagement by aheat responsive conductor, means tending to cause the movable contact member to contact with the stationary member, and means for passing synchronizing current through said conductor, thereby to close'said contacts periodically.

8. 'lhe method or synchronizing the .opera.- tion 0! a motor with the synchronizing signals, which consists in translating the signals into corresponding length variations in an expansible member, controlling the current supplied to the motor in accordance with said variations, and varying the effect of the said variations in accordance with the speed of the motor.

10. The method or synchronizing the operation or a motor with synchronizing signals, which comprises translating the signals into corre sponding variations in length or an expansible member, controlling the current supply to the motor in accordance with said variations, and varying the eti'ect ot the variations in accordance with the relative phase displacements between the angular rotation of themotor and the synchronizing impulses.

11. In a synchronizing system the combinationof means for producing synchronizing current variations, .a motor to be synchronized, a source of current for operating said motor, an expansible hot wire controlled by the synchronizing current, a circuit contact controlled by said hot wire, and adapted to control the application of current variations to said motor circuit, and an interrupter controlled by said motor'and acting conjointly with said hot wire to control the application of said current variations to said motor circuit.

12. An electric relay system comprising means for translating, current variations into corresponding variations in an expansiblehot wire, means for translating such hot wire variations into current variations in a motor circuit, and means controlled by said current variations for controlling the action oi said hot wire upon said motor circuit.

13. In a synchronizing system the combination of means for producing synchronizing current variations, a motor to be synchronized, a periodic circuit interrupter operated by said motor, a second circuit interrupter having a circuit connected to the source or synchronizing current and controlled by any expansible hot wire, and circuit connections whereby the operation of the motor is controlled by the conjoint action or said interrupters.

'CHARLEB FRANCIS JENKINS. 

